// MakeV1ConfigFromConfig creates an legacy V1 image config from an Image struct
func MakeV1ConfigFromConfig(img *image.Image, v1ID, parentV1ID string, throwaway bool) ([]byte, error) {
// Top-level v1compatibility string should be a modified version of the
// image config.
var configAsMap map[string]*json.RawMessage
if err := json.Unmarshal(img.RawJSON(), &configAsMap); err != nil {
return nil, err
}
// Delete fields that didn't exist in old manifest
imageType := reflect.TypeOf(img).Elem()
for i := 0; i < imageType.NumField(); i++ {
f := imageType.Field(i)
jsonName := strings.Split(f.Tag.Get("json"), ",")[0]
// Parent is handled specially below.
if jsonName != "" && jsonName != "parent" {
delete(configAsMap, jsonName)
}
}
configAsMap["id"] = rawJSON(v1ID)
if parentV1ID != "" {
configAsMap["parent"] = rawJSON(parentV1ID)
}
if throwaway {
configAsMap["throwaway"] = rawJSON(true)
}
return json.Marshal(configAsMap)
}
// MakeV1ConfigFromConfig creates an legacy V1 image config from an Image struct
func MakeV1ConfigFromConfig(img *image.Image, v1ID, parentV1ID string, throwaway bool) ([]byte, error) {
// Top-level v1compatibility string should be a modified version of the
// image config.
var configAsMap map[string]*json.RawMessage
if err := json.Unmarshal(img.RawJSON(), &configAsMap); err != nil {
return nil, err
}
// Delete fields that didn't exist in old manifest
delete(configAsMap, "rootfs")
delete(configAsMap, "history")
configAsMap["id"] = rawJSON(v1ID)
if parentV1ID != "" {
configAsMap["parent"] = rawJSON(parentV1ID)
}
if throwaway {
configAsMap["throwaway"] = rawJSON(true)
}
return json.Marshal(configAsMap)
}
// CreateV2Manifest creates a V2 manifest from an image config and set of
// FSLayer digests.
// FIXME: This should be moved to the distribution repo, since it will also
// be useful for converting new manifests to the old format.
func CreateV2Manifest(name, tag string, img *image.Image, fsLayers map[layer.DiffID]digest.Digest) (*schema1.Manifest, error) {
if len(img.History) == 0 {
return nil, errors.New("empty history when trying to create V2 manifest")
}
// Generate IDs for each layer
// For non-top-level layers, create fake V1Compatibility strings that
// fit the format and don't collide with anything else, but don't
// result in runnable images on their own.
type v1Compatibility struct {
ID string `json:"id"`
Parent string `json:"parent,omitempty"`
Comment string `json:"comment,omitempty"`
Created time.Time `json:"created"`
ContainerConfig struct {
Cmd []string
} `json:"container_config,omitempty"`
ThrowAway bool `json:"throwaway,omitempty"`
}
fsLayerList := make([]schema1.FSLayer, len(img.History))
history := make([]schema1.History, len(img.History))
parent := ""
layerCounter := 0
for i, h := range img.History {
if i == len(img.History)-1 {
break
}
var diffID layer.DiffID
if h.EmptyLayer {
diffID = layer.EmptyLayer.DiffID()
} else {
if len(img.RootFS.DiffIDs) <= layerCounter {
return nil, errors.New("too many non-empty layers in History section")
}
diffID = img.RootFS.DiffIDs[layerCounter]
layerCounter++
}
fsLayer, present := fsLayers[diffID]
if !present {
return nil, fmt.Errorf("missing layer in CreateV2Manifest: %s", diffID.String())
}
dgst, err := digest.FromBytes([]byte(fsLayer.Hex() + " " + parent))
if err != nil {
return nil, err
}
v1ID := dgst.Hex()
v1Compatibility := v1Compatibility{
ID: v1ID,
Parent: parent,
Comment: h.Comment,
Created: h.Created,
}
v1Compatibility.ContainerConfig.Cmd = []string{img.History[i].CreatedBy}
if h.EmptyLayer {
v1Compatibility.ThrowAway = true
}
jsonBytes, err := json.Marshal(&v1Compatibility)
if err != nil {
return nil, err
}
reversedIndex := len(img.History) - i - 1
history[reversedIndex].V1Compatibility = string(jsonBytes)
fsLayerList[reversedIndex] = schema1.FSLayer{BlobSum: fsLayer}
parent = v1ID
}
latestHistory := img.History[len(img.History)-1]
var diffID layer.DiffID
if latestHistory.EmptyLayer {
diffID = layer.EmptyLayer.DiffID()
} else {
if len(img.RootFS.DiffIDs) <= layerCounter {
return nil, errors.New("too many non-empty layers in History section")
}
diffID = img.RootFS.DiffIDs[layerCounter]
}
fsLayer, present := fsLayers[diffID]
if !present {
return nil, fmt.Errorf("missing layer in CreateV2Manifest: %s", diffID.String())
}
dgst, err := digest.FromBytes([]byte(fsLayer.Hex() + " " + parent + " " + string(img.RawJSON())))
if err != nil {
return nil, err
}
fsLayerList[0] = schema1.FSLayer{BlobSum: fsLayer}
// Top-level v1compatibility string should be a modified version of the
// image config.
transformedConfig, err := v1.MakeV1ConfigFromConfig(img, dgst.Hex(), parent, latestHistory.EmptyLayer)
if err != nil {
return nil, err
}
history[0].V1Compatibility = string(transformedConfig)
// windows-only baselayer setup
if err := setupBaseLayer(history, *img.RootFS); err != nil {
return nil, err
}
return &schema1.Manifest{
Versioned: manifest.Versioned{
SchemaVersion: 1,
},
Name: name,
Tag: tag,
Architecture: img.Architecture,
FSLayers: fsLayerList,
History: history,
}, nil
}